Valve actuating mechanism



Aug. 3, 1943. o. H. BANKER VALVE ACTUATING MECHANISM Filed Aug. 2, 1940 tNiiiNt'ii,

Patented Aug. 3, 1943 UNITED .iiJLIii' iiliiiiii STATES PATENT OFFICE VALVE ACTUATING MECHANISM Oscar H. Banker, Chicago, Ill., assignor to New Products Corporation, Chicago, Ill., a corporation of Delaware 12 Claims.

This invention relates generally to a valve actuating mechanism for internal combustion engines, and it is particularly directed to a portion of the mechanism commonly known as a valve lifter and operating as a silencer by eliminating clearance between the working parts.

The general object of the invention is to provide a self-contained valve lifter of new and improved construction.

Another object is to provide a valve actuating device of the hydraulic type comprising two telescopically engaged members, one of which abuts the valve stem of a valve mechanism while the other engages the valve actuating cam, together with improved hydraulic means functioning to maintain said two members extended and in operative contact with the stem and cam respectively for transmitting the force by which the valve is opened.

Still another object is to provide a self-contained valve lifter of a new and improved construction serving to render the mechanism extremely quiet under all operating conditions, as Well as economical to manufacture and simple to install, either in the Original construction of an engine or as a replacement device for noisy, worn or obsolete mechanism.

A further object is to provide a self-contained valve lifter of the hydraulic type wherein the spaces containing liquid by which the valve lifting force is transmitted are completely filled with such liquid to eliminate the possibility of churning. and to avoid excessive increase of pressure incident to an increase in temperature.

It is also an object to provide a self-contained valve lifter of the hydraulic type having a chamber filled with liquid through which the valvelifting force is transmitted, and a reserve chamber communicating therewith by way of a check valve, together with a restricted by-pass around the check valve to relieve expansion of the liquid in the first chamber upon a rise of temperature.

Other objects and advantages will become readily apparent from the following detailed description taken in connection with the accompanying drawing in which:

Figure 1 is a view partly in section, of a valve actuating mechanism for an internal combustion engine embodying features of this invention.

Figure 2 is an axial sectional view on a larger scale showing the internal structure of a valve lifter embodying one form of the invention.

Figure 3 is an end view of the structure shown in Figure 2.

Figure 4 is a face view of a check valve seat being taken as a section at line 4-4 on Figure 2.

Figure 5 is an axial sectional view of a modified construction embodying the invention.

Figure 6 is an end view of the device shown in Figure 5.

Figure 7 is a detail top plan view of thc valve Cage for the structure of Figure 5.

Fig. 8 is a fragmentary sectional view along the line 8 8 of Fig. 4, and showing the ball valve.

Fig. 9 is an enlarged fragmentary section along the line 9--9 of Fig. 5.

While the invention is disclosed in the drawing and is hereinafter described as embodied in two different forms, it should be understood that the invention is not limited to the specific embodiments disclosed. It is the intention to cover all modifications and alternative constructions falling within the spirit and scope of the invention, as defined in the appended claims.

Referring first to Figure 1 of the drawing, a portion of the cylinder block of an internal combustion engine is shown at I0, with a valve II`, having a head I2 which controls a port opening into a cylinder of the engine. The valve is mounted with its stem I3 extending slidably through a sleeve bushing I4 fixed in the cylinder block Ill. The valve stem carries a washer I5 with a compression spring IS interposed between the washer and the cylinder block I0 for urging the valve toward its seat. The valve is opened against the force ol the spring I6 by means of a cam I1 on a cam shaft I8, the necessary movement being transmitted through a valve lifter, generally designated I9, which is guided for longitudinal reciprocation in a bore formed in a portion of the cylinder block I0.

The present invention is directed more particularly to the valve lifter or actuating device I9 which is of the self-contained type. embodying a liquid as a cushioning and take-up means. In general, the valve lifter comprises two telescopically engaged parts or members, one in the form of a cylinder 2I, shown as having a head or enlargement 22 at its closed end, this head being maintained in Contact with the valve actuating cam Il. The other member is shown as a hollow plunger 23 having a cap 24 with a reduced projecting portion 25 which is maintained in Contact with the end of the valve stem I3. At the end opposite the cap 24 the end wall or head 26 of the plunger is formed with a port 2'l over which there is normally seated a check valve 28 held yieldingly to its seat by a spring 29 which is accommodated in a reduced extension 30 of the plunger. The valve and its spring are held in place by a terminal fitting 3| forced onto the reduced extension 3U and provided with a port or passage 32 having a shoulder 33 against which the spring 29 reacts.

Between the end wall 34 of the bore of the cylinder 2| and the head 26 of the plunger 23 there is formed a space 35 of quite limited extent. This space is partially occupied by a flexible, annular packing member 36 of the channeled, self-sealing type, and a leather washer 3'I interposed between the packing member and the head 26 of the plunger. The remainder of the space 35 is lled with liquid through which the valve actuating pressure is transmitted from the head 22 of the cylinder 2| to the plunger 23 telescoped therein, and thence by way of the projecting terminal 25 to the valve stem I3.

The cavity 38 of the hollow plunger 23 provides a reserve chamber for additional liquid which has relatively free access to the space 35 for replacing any loss of liquid therefrom. A piston 39 is slidably fitted Within the cylindrical bore of the plunger 23, and associated with the piston is a flexible, self-sealing packing element 40 in contact with the body of liquid in the reserve chamber 38. A coil spring 4| reacts between the piston 39 and the cap 24 of the plunger, thus providing self-contained means within the plunger for maintaining the reserve supply of liquid under pressure. This pressure is sufficient at all times to force liquid past the check valve 28 and through the passage 32 into the space 35 at the head end of the cylinder 2|, so that the lifter I9 shall serve to actuate the valve I3 efficiently, without play and without noise.

In assembling this form of the invention a suitable liquid (usually oil) is placed irrthe cylinder 2|, and the plunger 23 is installed therein in a. manner which avoids trapping any air in the space 35 or in the reserve chamber 38. When the cap 24 is fitted into the end of the plunger, with a quantity of liquid in the reserve chamber 38 thereof, the spring 4| is compressed, and the cap may be locked in place by one or more pins 42 engaging the depending skirt or flange of the cap with the cylindrical wall of the plunger 23. When the valve liitei` is to be installed in an engine, as illustrated in Figure 1, liquid under pressure in the reserve chamber 38 is forced past the check valve 28 into the head end chamber 35 until the two telescopic parts of the device are extended sufficiently to take up all clearance in the mechanism; but before installation, or upon removal of the device I9, its maximum extension is determined by a snap ring 43 inserted in a groove in the cylinder 2| near its upper end and engaging the outer face of the cap 24, as seen in Figure 2. During operation of the engine, any leakage past the plunger 23 during the valve lifting strokes, or due to expansion of the liquid or metallic parts upon a rise of temperature, is immediately replaced in the head end chamber 35 during the return strokes because of the pressure maintained on .the liquid in the reserve chamber by means of the piston 39 and spring 4 I.

During operation the liquid in the space 35 must withstand high temperature as well as high pressure, and for this purpose an oil of low viscosity, or a liquid commonly known as brake fluid," because of its use in hydraulic brakes, may be employed satisfactorily. To serve as a packing material in contact with such oil, a commercial product called Neoprene, made from coal and having some of the characteristics of rubber, is found suitable and efficient; but under high pressure, such as that encountered in the space 35, if the Neoprene packing is interposed wholly between metallic surfaces, there is a tendency for il; .to deform and become wedged into any slight crevice which may exist between such surfaces. Therefore, I interpose the washer 3l, of leather, between the Neoprene packing member 36 and the head of the plunger 23.

The outer surface of the plunger 23 is provided with helical oil grooves 44 extending through most of its length for distributing lubricating oil to insure easy movement and quick response in the telescopic action of the cylinder 2| and the plunger 23. Near the head end of the cylinder 2|, which will usually be the lower end, the cylinder is formed with outlet holes 45 through which the oil may escape after making its way from the upper end of the cylinder down through the grooves 44. To insure a supply of such lubrication the cap 24 of the plunger may be made with a clearancey or formed with inlet grooves at 46 through which oil will find its way along the wall of the cylinder 2| and into the grooves 44.

When the valve lifter I9 has been installed in the engine and fitted to its position between the cam Il and the valve stem I3, a rise of temperature might cause expansion of the liquid in the space 35 to an extent which would unduly extend the device lI9 if the check valve 28 provided a perfect seal for the port 2l. To meet such a situation the seat 4I for the valve 28 may be formed with a minute by-pass groove or bleed channel 48, as seen in Figure 4, to allow the gradual expansion of the liquid at 35 such as would occur upon a rise of temperature, to relieve itself by forcing a small quantity of the liquid back into the reserve chamber 38.

Figures 5 and 6 illustrate a modification in which the essential elements of the valve lifte: are considerably rearranged, but in which the principle of operation is the same as that of the structure already described. The cylindrical body 50 is formed with a head 5| at its closed end for contact with and operating cam (such as II of Fig. 1), and the upper end of the cylinder is open. Intermediate the ends, however, the bore of the cylinder is formed with a shoulder 52 against which there is lodged an inserted cylinder 53, with a plunger 54 longitudinally Slidable therein. The cylinder 53 is locked into the cylinder 50 by means of a snap ring 55. The upper end of the plunger 54 is in the form of a head 56 protruding from the open end of the cylinder 50 and adapted for engagement with the lower end of the valve stem I3. The protrusion of the part 56 is limited by a snap ring 5'I set in a groove in the wall of the cylinder 53 and engaging a beveled shoulder 58 of the plunger 54. As its lower end the plunger 54 is tted with a leather washer 59 and with a self-sealing flexible packing member 68 which directly contacts the liquid (usually oil) occupying the space 6I adjacent the head 62 of the cylinder 53.

The reduced bore of the cylinder 50, extending from its shoulder 52 to a point adjacent the head 5|, provides a reserve chamber at 53 for a supply of liquid to maintain the liquid at 6I under suitable pressure and to replace it if any should leak or escape during operation of the device. From the lower portion of the chamber 63 a feed pipe 64 leads upwardly, preferably in axial posi- -a piston composed of a metallic liquid in the space 6|,

1 with the check valve tion, and into connection with a depending reduced extension 85 of the cylinder head 6|. A pressure spring 66 reacts between the head 6| and disk 61, combined with a flexible, self-sealing packing member 69, and slidable along the feed pipe 64 within the cylindrical chamber 63. The upper end of the pipe 64 connects with a port 69 in the head 62 of the cylinder 53, and a check valve 10, in the form of a ball, is shown seated b'y gravity over this port. A cage 1|, tted into a suitable recess in the head 62 of the cylinder 53, loosely confines the ball to the vicinity of its seat, but permits it to be unseated for flow of liquid from the pipe 64 to the pipe 69 and into the space 6|. The cage 1| includes an outlet slot 12 extending radially and through one side wall of the cage, so as to prevent the ball 10 from ever closing this outlet in any position which the ball can assume. Thus, whenever the liquid in the space 6| requires replacement in order to maintain engagement of the head 5| with the cam I1, and contact of the head 56 with the stem I3, the constantly acting pressure of the spring 66 forces the piston 61, 68 downwardly, driving a portion of the liquid in the reserve chamber .63 into the pipe 64 and upwardly therethrough to the space 6 I Preferably, the seat 'I3 for the ball check-valve 1U will have a bleed groove or channel similar to that shown at 48 in Figure 4, for the check valve 28, so that while the valve 10 is normally seated to prevent iiow of liquid from the space 6| to the reserve chamber 63, the gradual expansion of the due to rise of temperature, may be relieved by the limited back-flow permitted through this bleed groove or by-pass.

The provision of a movable wall (in the form of piston 39 or piston 61) for the reserve chamber opening outwardly from the reserve chamber, serves to maintain all the liquid in the device under pressure and thus insure that both chambers of the device will be lled with liquid at all times, This eiectively excludes air from the chambers and prevents the churning of the liquid which might otherwise be encountered, as in a construction employing a spring to extend the telescoping parts and relying upon suction to draw liquid from the reserve chamber when required. The maintenance of pressure on the liquid also prevents the oil from being converted into gas or vapor. An increase of pressure in the liquid, due to an increase of temperature, is accommodated in the reserve chamber by the yieldable spring 4| or 66 whichA backs up the movable wall, and, as already explained, the bleed port 48 will relieve excessive pressure from this cause in the space or 6|.

Preferably, the end Wall 34 of the cylinder 2| is concavely rounded to conform to the convex end of the fitting 3| which serves as a terminal for the plunger 23, and the normal distance between these parts is comparatively slight s@ that the space 35 contains only a relatively small quantity of liquid. If, for any reason, this liquid should be dissipated or omitted, these opposing surfaces of the end wall 34 and the terminal fitting 3| will come into contact for transmitting movement from a cam |1 to the valve stem I3, even for continuous'operation of the engine; and these contacting surfaces are of suillcient area to endure such operation, even in the absence of the usual-cushioning effect of the liquid. With the -construction shown in Figure 2 it is possible to leave an extremely, small amount of clearance between the end wall 34 and the terminal 3| Cal even less than that shown in the drawing, if desired; this will hold the plunger 23 to a short range of travel so that in the event the liquid is lost or omitted, the valve I2 will be Furthermore, transmitted by a spring between the cylinder and plunger of the device 9, there is no chance of spring breakage resulting in fragile parts which would be crushed or jammed in the interior of the device in the absence of liquid therein. When the construction shown in Figure 5 is employed, there is likewise the possibility of continued operation even if the liquid at 6| should be lost or omitted. In this event the under surface 56 of the head 56 on the upper end of the plunger 54 will descend to engage the upper end of the cylinder 53, thus providing a direct metallic connection for transmitting movement from the cam |1 to the valve stem I3.

In assembling the form of the invention illusi the cylinder 2| is rst lled trated in Figure 2, with oil up to the level of the openings 45. Thereupon the plunger 23 with the annular packing member 36 and washer 31 assembled thereon, as well as the parts 3|, 29 and 28, is moved in through the top opening of the cylinder and down until the annular packing member 36 extends a short distance below the openings 45. During this movement the check valve 28 is depressed by means of a suitable rod so as to permit the oil trapped in the lower end of the cylinder to ow upwardly through the port 21. The device is then inverted so that any air trapped in the annular groove of the packing member 36 moves upwardly to the end of the cylinder of a rod, the plunger assembly is pushed all the way up into the cylinder, this action carrying the air out with the additional oil. Thereafter the device is placed upright and the proper quantity of oil filled into the cavity 38. The packing element 40 is then pushed downwardly within the plunger 23, preferably with a small wire or rod in between one the packing element movement of the packing member 40 the device is preferably tilted to such an extent that it is almost in a horizontal position whereupon any air trapped under the packing member 46 will collect below the peripheral member and prlncipally on during the withdrawal of the wire so that the oil lls the space in the cavity which has been occupied by the wire.

in the plunger until it engages the packing mem- Then the piston 39 is inserted ber 40. Now, when pressure is exerted against the piston 39, as by means of a suitable arbor press, fluid from the cavity 38 flows downwardly through the port 21 past the check valve 28 and into the space 35, with the result that the plunger is'ralsed in the cylinder 2| until the upper end of the plunger extends above the upper end 'of the cylinder 2| sufficiently to expose the opening for the head of the pin 42. The spring 4| is then inserted and the cap 24 is placed in proper plosition on the upper end of the plunger 23; then the I the ports 32 and 21 and the bleed channel 4|!` into the cavity 38. h

In the form illustrated in Figure 5, the vdevice may be assembled by first fitting the parts 53, 1| and 64 together, these parts being secured together by press fits, and the ball check valve 18 being properly placed before the cage 1| is secured in the head of the cylinder 53. Thereafter the packing member 60, together with the leather washer 59 and the plunger 54, is inserted in the cylinder 53, the snap ring 51 being assembled around the reduced portion adjacent the beveled shoulder 58 of the plunger 54 so that it is carried downwardly within the cylinder 53 until it engages in the groove provided to receiveit. After these parts have been assembled, they are inverted so that iluid can be inserted through the then upper end of the pipe 64 until it fills entirely the pipe, the cage 1|, and any space within the g cylinder 53. During the oil filling operation, the oil being inserted under pressure, the plunger 54 moves to the position shown in Figure (although the device is still inverted) so that the beveled shoulder 58 engages the snap ring 51. While still in inverted position a suitable rod is inserted through the pipe 64 so as to unseat the check valve while the plunger 54 is pressed inwardly to its innermost position, this action forcing any entrapped air and excess oil out through the L upper end of the pipe. Leaving the plunger assembly in its inverted position momentarily, the assembly of the device proceeds by filling the lower end of the cylinder with fluid up as far as the openings 8|. The packing member 68 is then pressed into the cylinder 50 far enough to bring the upper surface of the packing member approximately level with the lower edges of the opening 8|. In order to prevent trapping of fluid in the annular channel in the under side of the r packing member 68, a suitable J -shaped tube can be passed through the central opening in the packing member and held with its lower end in the upper portion ofY the channel to let the air pass out. Alternatively, the channel in the packingmember might be filled with grease or other substance which is soluble in the fluidi so that during the assembling operation there is no space within which air can become entrapped.. With the packing member in the position just described the metal disk 61 is placed thereon and the spring 66 is placed within the cylinder 50 in the approximate position shown in Figure 5. With the cylinder 50 remaining upright the previously inverted assembly of the plunger 53 and associated parts, including the pipe |54, can be placed upright, the uid being retained in the pipe 64 due to the fact that the pipe is sufficiently small in diameter so that no air can pass upwardly therein. Since the pipe 64 is then filled to its lower end, and the chamber 63 is completely filled to the upper level of the packing member 68, the pipe can be inserted through the metal disk 61 and through 'the packing member` 68 (the centrai aperture in the disk being sufiiciently large to leave clearance outside of the pipe 64 through which air may escape). With the snap ring positioned around the plunger 54 immediately below the head 56 thereof, so that it will enter within the upper end of the cylinder 50, the plunger assembly is then pressed downwardly as, for example, in an arbor press, applying pressure to the head 56 until the cylinder 53 moves downwardly sufficiently to permit the snap ring 55 to expand into its groove. The parts are then in their finally assembled position and the device is ready for operation.

It is the intention that the movable walls or pistons associated with the reserve chambers shall be subject substantially -to atmospheric pressure or to the normal pressure within the engine block. For this reason the plunger 23 is provided with ports 80, and the cylindrical member 50 of Figure 5 has lateral ports 8| disposed opposite the space between the upper side of the piston member 61 and the lower side of the cylinder head 82. The ports 80 communicate with the interior of the engine block, both by way of the clearance spaces 46 and through the helical oil grooves 44 which discharge through ports 45 in the cylinder 2|. This prevents the accumulation of oil or other liquid which might otherwise fill up the space back of the piston and prevent the normal yielding operation of the spring 4| or the spring 66. Oil passing out through openings 80 or 8| serves to lubricate the bearing surface oi the bore 20 in which the device operates.

The invention thus provides an extremely compact structure in which the liquid maintained under pressure in the reserve chamber serves as a means for extending the parts for efficient operation, but which is even adapted to function continuously if the liquid normally contained in the device is absent.

It will be understood that the use of self-sealing packing elements in both forms of the invention herein disclosed tends to prevent any substantial leakage of the liquid and to maintain the devices at full efficiency over long periods of time.

'The element 36, having a downwardly facing channel to which the liquid in the space 35 has access, will have both walls of its channel pressed firmly into contact with the part 3| and the interior of the cylinder 2| by pressure of theliquid at 35, which it is the function of the element 35 to seal. Similarly, the pressure in the cavity 38 acts laterally against the depending skirt or 'flange of the sealing member 4Il so as to force this ange portion of the member into sealing engagement with the inner wall of the hollow plunger 23. In Figure 5 the element 68 has a downwardly facing channel into which the liquid under pressure at 63 rises so as to force the walls of the channel into sealing engagement with the central tube 64 and the inner wall of the cylinder 50. And in the upper portion of this structure the sealing member is formed with a depending flange so that the lateral pressure of the liquid in the central cavity of the element 60 thus formed serves to press the flange of the member into sealing engagement with the wail of the cylinder 53. In each instance the pressure of the liquid thus seals itself through the medium of these flexible flanged elements, and an increase of pressure only tends to increase the efficiency of the seal.

I claim as my invention:

l. A valve actuating device comprising, in combination, a member forming a cylinder closed at one end, a hollow/plunger fitted slidably in said plunger toward the open end thereof.

2, A valve actuating device comprising, in combination, a member forming a cylinder closed at one end, a hollow plunger tted slidably in said cylinder with a part projecting from the open end of the cylinder, the cavity of the plunger serving as a reserve chamber for liquid, a check valve device in the plunger permitting liquid to flow freely from said chamber to a space between the closed end of the cylinder and the end of the plunger, a piston in the plunger forming one wall of the reserve chamber and a spring in the plunger reacting against the pistonl in a direction tc contract the reserve chamber and maintain the liquid therein under pressure sufficient to force liquid into the head end of the cylinder and move the plunger toward the open end thereof, together with stop means on the cylinder engageable with the plunger to limit such movement.

3. A valve actuating device comprising, in combination, a member forming a cylinder closed at one end, a hollow plunger fitted slidably in said cylinder with a part projecting from the open end of the cylinder, the cavity of the plunger serving as a reserve chamber for liquid, a check Valve device in the plunger permitting liquid to flow freely from said chamber to a spacebetween the closed end of the cylinder and the end of the plunger, a piston in the plunger forming one wall of the reserve chamber and a spring in the plunger reacting against the piston in a direction to contract the reserve chamber and maintain the liquid therein under pressure suiiicient to force liquid into the head end of the cylinder and move ;he plunger toward the open end thereof, to- :ether with a flexible packing member of the ielf-sealing type at the end of the -plunger adja- :ent the closed end of the cylinder, and a. leather vasher interposed between said packing member .nd the plunger.

4. A valve actuating device comprising, in comination, a member forming a cylinder closed at ne end, a hollow plunger tted slidably in said ylinder with a removable cap secured to one end losing the cavity of the plunger andhaving a art projecting from the open end of the cyliner, the cavity of the plunger serving as a reserve namber for liquid, a check valve device in the iunger permitting liquid to flow freely from said iamber to a space between the closed end of le cylinder and the end of the plunger, a piston the plunger forming one wall of the reserve iamber and a spring in the plunger reac-ting befeen the cap and said piston in a direction to ntract the reserve chamber and maintain the luid therein under pressure suflicient to force Luid into the head end of the cylinder and move e plunger toward the open end thereof. 'A valve actuating device comprising, in nbination, a member forming a cylinder closed one end, a hollow plunger fitted slidably in d cylinder with a part projecting from the en end of the cylinder, the cavity of the plung- 5 er serving as a reserve chamber for liquid, a check valve device in the plunger permitting liquid to ow freely from said chamber to a space between the closed end of the cylinder and the end of the plunger, resilient self-contained means in the device including a restricted by-pass permitting liquid to escape past the valve into the reserve chamber upon expansion due to increase of temperature.

6. Inthe combination defined in check-valve device including a restricted bypass crease of temperature.

7. A vvalve actuating device comprising, combination, a member ber and maintain the liquid therein under pressure sulicient to force liquid into the space between the plunger and the head and urge the plunger toward the open end of the cylinder.

8. A valve actuating device comprising, in

the space between the plunger and the head and urge the plunger toward the open end of the cylinder, and a feed passage extending from the check valve through said piston into the reserve chamber.

9. A valve actuating device comprising, in combination, a member forming a cylinder closed at one end, a head xed in the cylinder intermediate its ends, a plunger slidably iitted in the cylinder at one side of said head, spaced therefrom, the space between the other side of said head and the closed end of the cylinder including a reserve chamber for liquid, a port providing communication between the space on one side of said head and the space at the other side of the head, a check valve controlling said port and permitting the liquid to ilow freely from the reserve chamber to the space between the plunger and the head, a piston in the space which includes the reserve chamber forming one wall of said chamber, a feed tube connecting the end of said reserve chamber'remote from the piston with the port controlled by said check valve, and a spring reacting expansively between the head and the piston tending to contract the reserve the liquid therein under pressure sutiicient to force liquid into the space between the plunger and the head for urging the plunger toward the open end of the cylinder.

10. A valve actuating device comprising, in combination, a member forming a cylinder closed at one -end andopen at the other end, the bore of the cylinder having a shoulder facing the open end, a hollow cylinder open at one end and provided with a head at the other end, said cylinder being inserted in said member with its head stopped against the shoulder, retaining means locking said cylinder in place, a plunger slidably tted in said cylinder and spaced from its head, the space between the other side of said head and the closed end of the cylinder including a reserve chamber for liquid, said head having a passage communicating with the reserve chamber, a check valve in said passage arranged to permit liquid to flow freely from said chamber to the space at the other side of the head, and means in the space which includes the reserve chamber maintaining the liquid therein under pressure suiiicient to force said liquid into the space between the plunger and the head andurge the plunger toward the open end of the cylinder.

11. A valve actuating device comprising, in combination, a cylinder member closed at one end and open at the other end, a plunger member fitted slidably in the cylinder member with a part projecting from the open end thereof, the cylinder member having affixed head and the plunger member being spaced therefrom with liquid interposed between the head and thev plunger, one ofthe members providing a reserve chamber containing additional liquid with yielding means maintaining said liquid under pressure, said chamber having a port affording com- \munication between said chamber and the space "between the head and the plunger, and a check valve device which includes a valve seat at said port and a movable valve member seating toward the reserve chamber and unseating toward said space providing a passage for the free flow ofthe liquid from the reserve chamber to said space, but resisting return iiow, device including a restricted by-pass formed as a minute channel in the seating surface of the valve seat affording access past the valve in its seated -position and connecting said space with the reserve chamber, whereby return ow of the liquid may occur upon expansion due to increase of temperature.

123A valve actuating device comprising, in combination, acylinder member closed at one end and open at the other end, a plunger member tted slidably in the cylinder member with a part projecting from the open end thereof, the cylinder member having a fixed head and the plunger member being spaced therefrom with liquid interposed between the head and the plunger,`one of the members providing a reserve chamber containing additional liquid with a port affording communication between said chamber and the space between the head and the plunger, and a check valve device which includes a valve member and a seat therefor at said* port, said valve member unseating toward the said space and providing a passage for the free flow of the liquid from the reserve chamber to said space but resisting return flow, said check valve device including a restricted by-pass formed as a minute channel in the seating surface of the valve seat and connecting the said space with the reserve chamber when the valve is seated, whereby return ow of the liquid may occur upon expansion due to increase of temperature.

OSCAR H. BANKER.

said check valve 

